(a) Field of the Invention
The present invention relates to a mitre box construction wherein the saw blade is captive on each side of the mitre box in guide elements which are arcuately displaceable on a common diametrical axis whereby the saw blade is precisely maintained along a desired angle.
(b) Description of Prior Art
Various types of mitre box constructions are known. The mitre box of this invention relates to the type of boxes wherein the saw blade is held stationary along a desired angle by guiding the saw blade at spaced apart locations on each side of the mitre box. A disadvantage of the conventional mitre box where the saw blade is guided in precut slots made in opposed side walls of the box, is that these slots become enlarged and distorted by repetitive sawing motion of a saw blade extending therethrough and the blade is no longer guided at an accurate angle. Such type boxes usually have slots to guide the saw at two 45.degree. angles and one 90.degree. angle. This type of mitre box is also limited as to the number of angles at which the saw blade can be guided. However, other types of mitre boxes are known wherein the saw blade can be guided at any angle within a desired 90.degree. range. A disadvantage of some of these further types of mitre boxes is that the saw blade cannot be maintained precisely along a desired angle as the saw blade is reciprocated as it is held by a single guide means, such as in U.S. Pat. No. 600,118. A further disadvantage of the mitering device as taught by that patent is that the saw guide support is complex in construction and difficult to adjust on the machine. Furthermore, the saw blade is guided at a position to one side only of the workpiece being cut. Thus, the saw blade may be distorted in the area where the cut is being made, particularly if the cut in the material becomes slightly displaced and the groove made by the cut continues to guide the loose end of the saw blade in the direction of the displaced angle. Thus, the saw guide support is not effective. In the present application, there is used guide elements generally of the type as taught in this reference, but used in a different system requiring simple and effective adjustments and proper guiding of the saw blade.